Method inlining across dex files in boot image.

Fix LoadCodeAddress() and LoadMethodAddress() to use the dex
file in addition to the method index to uniquely identify
the literal. With that fix in place, when we have both the
direct code and the direct method, we can safely pass the
actual target method id instead of the method id from the
same dex file in the method lowering info. This was already
done for calls from apps into boot image (and thus there was
a bug with a tiny risk of the wrong literal being used) and
now we also do that for calls within the boot image. The
latter allows the inlining pass to inline many more methods
than before in the boot image.

Bug: 15021903
Change-Id: Ic765ce9809b43ef07e7db32b8e3fbc9acb09147f

3 files changed, 37 insertions, 26 deletions

diff --git a/compiler/dex/quick/codegen_util.cc b/compiler/dex/quick/codegen_util.cc
index d58015a979..a3c94ed103 100644
--- a/compiler/dex/quick/codegen_util.cc
+++ b/compiler/dex/quick/codegen_util.cc
@@ -364,6 +364,18 @@ LIR* Mir2Lir::ScanLiteralPoolWide(LIR* data_target, int val_lo, int val_hi) {
   return NULL;
 }
 
+/* Search the existing constants in the literal pool for an exact method match */
+LIR* Mir2Lir::ScanLiteralPoolMethod(LIR* data_target, const MethodReference& method) {
+  while (data_target) {
+    if (static_cast<uint32_t>(data_target->operands[0]) == method.dex_method_index &&
+        UnwrapPointer(data_target->operands[1]) == method.dex_file) {
+      return data_target;
+    }
+    data_target = data_target->next;
+  }
+  return nullptr;
+}
+
 /*
  * The following are building blocks to insert constants into the pool or
  * instruction streams.
@@ -1143,11 +1155,13 @@ void Mir2Lir::AddSlowPath(LIRSlowPath* slowpath) {
 
 void Mir2Lir::LoadCodeAddress(const MethodReference& target_method, InvokeType type,
                               SpecialTargetRegister symbolic_reg) {
-  int target_method_idx = target_method.dex_method_index;
-  LIR* data_target = ScanLiteralPool(code_literal_list_, target_method_idx, 0);
+  LIR* data_target = ScanLiteralPoolMethod(code_literal_list_, target_method);
   if (data_target == NULL) {
-    data_target = AddWordData(&code_literal_list_, target_method_idx);
+    data_target = AddWordData(&code_literal_list_, target_method.dex_method_index);
     data_target->operands[1] = WrapPointer(const_cast<DexFile*>(target_method.dex_file));
+    // NOTE: The invoke type doesn't contribute to the literal identity. In fact, we can have
+    // the same method invoked with kVirtual, kSuper and kInterface but the class linker will
+    // resolve these invokes to the same method, so we don't care which one we record here.
     data_target->operands[2] = type;
   }
   LIR* load_pc_rel = OpPcRelLoad(TargetReg(symbolic_reg), data_target);
@@ -1157,11 +1171,13 @@ void Mir2Lir::LoadCodeAddress(const MethodReference& target_method, InvokeType t
 
 void Mir2Lir::LoadMethodAddress(const MethodReference& target_method, InvokeType type,
                                 SpecialTargetRegister symbolic_reg) {
-  int target_method_idx = target_method.dex_method_index;
-  LIR* data_target = ScanLiteralPool(method_literal_list_, target_method_idx, 0);
+  LIR* data_target = ScanLiteralPoolMethod(method_literal_list_, target_method);
   if (data_target == NULL) {
-    data_target = AddWordData(&method_literal_list_, target_method_idx);
+    data_target = AddWordData(&method_literal_list_, target_method.dex_method_index);
     data_target->operands[1] = WrapPointer(const_cast<DexFile*>(target_method.dex_file));
+    // NOTE: The invoke type doesn't contribute to the literal identity. In fact, we can have
+    // the same method invoked with kVirtual, kSuper and kInterface but the class linker will
+    // resolve these invokes to the same method, so we don't care which one we record here.
     data_target->operands[2] = type;
   }
   LIR* load_pc_rel = OpPcRelLoad(TargetReg(symbolic_reg), data_target);
diff --git a/compiler/dex/quick/mir_to_lir.h b/compiler/dex/quick/mir_to_lir.h
index 7f0bf30e68..454365ae14 100644
--- a/compiler/dex/quick/mir_to_lir.h
+++ b/compiler/dex/quick/mir_to_lir.h
@@ -610,6 +610,7 @@ class Mir2Lir : public Backend {
     LIR* NewLIR5(int opcode, int dest, int src1, int src2, int info1, int info2);
     LIR* ScanLiteralPool(LIR* data_target, int value, unsigned int delta);
     LIR* ScanLiteralPoolWide(LIR* data_target, int val_lo, int val_hi);
+    LIR* ScanLiteralPoolMethod(LIR* data_target, const MethodReference& method);
     LIR* AddWordData(LIR* *constant_list_p, int value);
     LIR* AddWideData(LIR* *constant_list_p, int val_lo, int val_hi);
     void ProcessSwitchTables();
diff --git a/compiler/driver/compiler_driver.cc b/compiler/driver/compiler_driver.cc
index eb62f1b577..b8c33a07e0 100644
--- a/compiler/driver/compiler_driver.cc
+++ b/compiler/driver/compiler_driver.cc
@@ -1152,28 +1152,22 @@ void CompilerDriver::GetCodeAndMethodForDirectCall(InvokeType* type, InvokeType
       *type = sharp_type;
     }
   } else {
-    if (compiling_boot) {
+    bool method_in_image = compiling_boot ||
+        Runtime::Current()->GetHeap()->FindSpaceFromObject(method, false)->IsImageSpace();
+    if (method_in_image) {
+      CHECK(!method->IsAbstract());
       *type = sharp_type;
-      *direct_method = -1;
-      *direct_code = -1;
+      *direct_method = compiling_boot ? -1 : reinterpret_cast<uintptr_t>(method);
+      *direct_code = compiling_boot ? -1 : compiler_->GetEntryPointOf(method);
+      target_method->dex_file = method->GetDeclaringClass()->GetDexCache()->GetDexFile();
+      target_method->dex_method_index = method->GetDexMethodIndex();
+    } else if (!must_use_direct_pointers) {
+      // Set the code and rely on the dex cache for the method.
+      *type = sharp_type;
+      *direct_code = compiler_->GetEntryPointOf(method);
     } else {
-      bool method_in_image =
-          Runtime::Current()->GetHeap()->FindSpaceFromObject(method, false)->IsImageSpace();
-      if (method_in_image) {
-        CHECK(!method->IsAbstract());
-        *type = sharp_type;
-        *direct_method = reinterpret_cast<uintptr_t>(method);
-        *direct_code = compiler_->GetEntryPointOf(method);
-        target_method->dex_file = method->GetDeclaringClass()->GetDexCache()->GetDexFile();
-        target_method->dex_method_index = method->GetDexMethodIndex();
-      } else if (!must_use_direct_pointers) {
-        // Set the code and rely on the dex cache for the method.
-        *type = sharp_type;
-        *direct_code = compiler_->GetEntryPointOf(method);
-      } else {
-        // Direct pointers were required but none were available.
-        VLOG(compiler) << "Dex cache devirtualization failed for: " << PrettyMethod(method);
-      }
+      // Direct pointers were required but none were available.
+      VLOG(compiler) << "Dex cache devirtualization failed for: " << PrettyMethod(method);
     }
   }
 }